Automatic internal grinding machine



Sept. 7, 1937. K. JUNG 2,092,215

AUTOMATIC INTERNAL GRINDING MACHINE Filed Jan 29', 1936 2 Sheets-Sheet 1 Inventor Kar'Z Jung "7 Attorney Sept. 7, 1937. 4 JUNG 2,092,215

AUTOMATIC INTERNAL GRINDING MACHINE Filed Jan. 29, 1936 2 Sheets-Sheet 2' It'll/60:0! Ker Z (74/ 729 Patented Sept. 7, i937 UNITED STATES PATENT I OFFICE 1 AUTOMATIC INTERNAL GRINDING MACHINE Karl Jung, Berlin, Germany lilClaims.

In'internal grinding machines, in which the feed and cross-feed of the grinding wheel, the r nding motion and the operation oi truing the grinding wheel have to be controlled automatically as soon as the work has been clamped and the machine has been set in motion, that is to say, in the case of so-called automatic intemai grinding machines, the control of the various operations has been effected heretofore hydraulically or electrically. Neither of these two methods of control functions absolutely satisfactorily. In the case of electrical control, accurate operation of the contacts cannot be attained, and likewise in the case of hydraulic control in machines of high output, accurate reversing operations cannot be attained.

According to the invention an automatic internal grinding machine, in which the position of all the parts at the end of each cycle of working operations is the same as the position atthe commencement of the working cycle, is characterized in that for carrying out all the control movement for the'feed of the tool, work and truing tool, cams, cam, discs or the like are emloyed, which cams, cam discs or the like are driven by a cam shaft which makes one complete revolution during one worlnng cycle, while the actual feed movements are carried out by any mechanical, hydraulic or the like gears, said cam shaft being turned by two means each driving it during a part of each revolution.

Thereby the disadvantage of the existing methods of automatic control for such machines is obviated, and the control operations areeffected in absolute dependence upon one another and in absolutely the'correct sequence and directly one after the other so that high outputs can be ensured in the shortest conceivable time.

The accompanying drawings show diagrammatically by way of constructional example the driving device of an internal grinding machine according to the invention in which Figs. 1a and 11; together is a diagrammatic view of the env the machine, and Fig. 2 is a side view of a detail;

In the drawings I is the reciprocating table of an internal grindingmachine on which is mounted in known manner the device for receiving and drivingv the work to be ground. This table is reciprocated hydraulically, namely by a 1 piston 2 moving in a cylinder 3. The piston rod 20 is connected to the table I by means of an intermediate member 2b.

For reversal, there are provided on the table stops 4 and 5 adjustable in the longitudinal direction of the table, which stops abut against a -butt strap 6. The latter is mounted in a lever 1, la, adapted to rock about a pin lb. The arm y la is constructed in lmown manner as a knifeedge and co-operates with a roof-shaped lever 8 to produce complete reversal after the commencement of the feed operation. The roof-shaped lever 8 is under the influence of a spring.

The oil pressure for the hydraulic piston 2 is produced by a pump 9 which is set in rotation in any desired manner, not shown in the drawings, ofi the main drive of the machine. The oil is pumped past a pressure-relief valve l0 into a conduit II, which opens into the casing of a changeover valve l2. The change-over valve I2 is in the form of a piston valve and operates so that, according to the position of the piston, the recess provided in the piston connects the conduit H alternately with the conduit l3 or with a conduit IS. A spring H9 holds the valve in the position shown in the drawings in which the oil under pressure flows to the conduit i3. The conduit l3 opens into the cylindrical chamber of a throttle valve ll which is likewise in the form of a piston valve and by means of which the quantity of oil under pressure which can flow through the conduit l3 and to the conduit l5 may be regulated; the valve I4 is illustrated in the closed position-and the manner of its actuation will be described thereafter. Connected to the conduit is is a reversing valve l8 which, in the position shown in the drawings, connects the conduit IS with the conduit II, which leads to one side of the cylinder 3 and when it is reversed brings the conduit l5 into communication with the conduit l8 which leads to the second side of the cylinder 3. The conduit I'I or I8 which in each case is not in communication with the conduit I5, is connected by the reversing valve I6 to a discharge conduit l9 which returns the oil under pressure to the-oil tank 20.

For driving the automatic feed device there is a further hydraulic mechanism to which oil is supplied by a pump 2|, preferably mounted on the same shaft 2la as the pump 9. Both pumps 9 and 2i draw from the oil tank 20 and the oil from the pump 2| is conveyed by a conduit 22 to the gear box 23, which is merely indicated in the drawings by its outline. Connected in front thereof is a stopping and starting valve 24 and the latter, in the position shown in the drawings, in which it is held against the action 0! the spring 86, connects the supply conduit 22 with the gear box. If the spring 96 can operate and change over the valve, the conduit 22 is not shown in the drawings. The oil under pressure passing through the gear box is returned to the oil tank through the conduit 25a.

, The hydraulic gear 23 rocks an arm 26 to and fro in knownmanner. The said arm is connected by a link 21 to a pawl lever 28 of a ratchet device, so that upon the reciprocation of the arm 26, the ratchet wheel 26a together with the shaft 28b on which the ratchet wheel is mounted is rotated. The shaft 26b acting through three gear wheels 29 drives the shaft 36 on which are mounted all the cams necessary for the automatic control. These control cams aredenoted by 3l-31. The end of the shaft 30 is connected by bevel gears 36 to a shaft 39 which in its turn drives a shaft 4| through bevel wheels 40. Mounted on the said shaft 4| is a cam 4la which controls the crossfeed of the grinding wheel. The mounting of the grinding wheel and the method of its crossfeed may=- be as desired. In the constructional example, it is assumed that the grinding wheel During one revolution of the shaft 36, complete machining of an article is effected. The

rotation of the shaft 36 during one part of the working operation is eflected by the ratchet mechanism 26-28- ofi the driving gear 23 which regulates the cross-feed of the grinding wheel. During another part of the revolution, on the contrary, rotation of the shaft 36 is effected 01 the reciprocating table. I. These working operations which are closely connected with the crossfeed of the grinding wheel, namely roughing and finishing are carried out in agreement with the cross-feed 'of the grinding wheel, while the other working operations, that is to say, the truing of the grinding wheel and the exchange of the work are dependent upon the position of the table I and consequently must be controlled in close relationship with the table movement.

For rotating the shaft 30 by the table I, a roof-shaped cam 42 is provided on the latter,

.the said stop being adapted to co-operate with a roller-43. As long as the work is being machined, the table I reciprocates in the'usual manner, being actuated by the hydraulic gear 2, 3, reversal taking place by rocking of the lever 1 which is connected to the stop 6 and which of course reciprocates the reversing valve is. As soon as machining .is completed, the

strap 6 is removed out of the path of the stop 6. After the stop 5 has passed by, the strap is again lowered so.as to come into contact with the stop H8. This takes place by means of the cam 32. This cam and also the other cams 34-31 have been shown in the drawings ,merely as circles. The shapes which these cams must have follow at once from their mode of operation. The cam 32, therefore, at the moment at which the machining of the work is completed must have a descending part, so

that the nose of the bell-crank lever 48 can drop in. The bell-crank lever consequently moves under the action of a spring 49 in the clockwise direction, it draws the rod 56 with it and thereby rotates an eccentric 5lmounted on the pin lb. Bearing against this eccentric 5! is a rod ,52 which is carried on the upper arm I of the bell-crank lever and has its. upper end'pivoted lever 43a carrying the roller 43 is thereby rocked so that the pull rod 53 is raised against the action of the spring 53a carrying with it the pawl 54 which engages the ratchet wheel 33 on the shaft 30, so that the shaft- 36 is thereby rotated further by a certain amount in accordance with the movement of the table. The ratchet wheel 33 has four tooth gaps denoted by I-IV. According to the position of the shaft 30, the pawl 54 at the moment at which the table effects the rotation of the shaft 30, always engages one of these tooth gaps, thereby rotating the shaft 30 through a certain amount. During one revolution, therefore, a rotary movement of the shaft 36 is effected four times by the table.

Provided on the table I are two further cams 44 and 46 co-operating with rollers 45 and 41. The cams 42, 44 and 46 and the corresponding rollers lie in different vertical planes so that they do not interfere with each other intheir operation. When after the stop 6 has been rendered inoperative, the table moves to the left in the drawings, the cam 42, as already mentioned, will have first become operative. A length of time later, namely at the end of the left-hand stroke the cam 44' becomes operative and then rocks the bell-crank lever 45a.carrying the roller 45 in an anti-clockwise direction. The said lever is held by a spring 61 in abutment with a stop pin. Pivotally mounted abouta pin 65 on the end of the second lever arm of the bell-crank lever 45a is a rod 55. The latter is held by a 'spring'55a. against a stop pin-in the position Consequently, if due to the action of the cam 44 the rod 55 makes a movement to the right in the drawings, it rocks the rod 59 in a clockwise" direction. The rod 62, which is connected to the rod 59, is thereby also moved and the latter abuts against a valve 63. This valve which is normally held closed by a spring 66, is situated in the conduit 11 leading 'to the left-hand side of, the cylinder 3. The opening of the valve 63 renders the conduit I l pressure-less because the oil flowing to it will now flow past the valve.

The table consequently cannot begin its righthand stroke and remains stationary in its outer-.

most lefthand position. This position,- in which the cam 44 lies above the roller 45, is that in which the work is exchanged. Shortly before this end position is reached the reversing valve I6 is shifted by means of a stop l2! in a manner hereinafter described. 7

For re-starting the machine after exchanging the work, there is provided a push knob 64, whereby the rod 55 can be lifted against the action of the spring 55a, so that its nose 66 releases the lever 59. Consequent y. the valve 63 can close again under the action of the spring 66 and the working operation can commence. When the cam 44 releasesthe roller 45, the bellcrank lever 45a under the action of the spring 61 can also return'with the rod 55 into its initial position again, since the rear end of the nose 60 is bevelled, so that the rod 55 is=lifted over 5 the upper end of the rod 59.

In a certain position of the table I during its movement to the left the cam 46, as above described, comes into engagement with the roller 4! of a double lever, which thereby lifts the rod m 68. The bell-crank lever 69 is thereby rotated, the said bell-crank lever beingnormally held by the spring 9| in abutment against a pin 92, and

the abutment surface I of this lever swings outwardly to the left in the drawings. This abutment surface I0 co-acts with the abutment surface II of a rod I2. The said rod is pivoted by its second end to a. double lever I5, the free end of which bears against the valve I2. In the vicinity of the pressure surface II of the rod is pivoted a link I4, the lower end of which engages the cam lever I3. The cam lever I3 cooperates with the cam 31 and is held by a spring 13a against the said cam. The cam 31 is shaped so that the cam lever I3 can be set by it in two in drawings, it holds the abutment surface II below the path of the abutment surface I0- of the lever 69, and in the other position, that is to say, when the nose of the lever I3 can drop into a recess of the cam 31, the abutment surface II comes in front of the abutment surface I0. When the abutment surfaces I0 and II are opposite to one another, the movement of the cam 45 over the-roller 41 causes the rod I2 to move to the left. The valve I2 is thereby thrown over against the action of the spring 9, and the pressure liquid pumped by the pump 8 no longer flows through the conduit l3 and I5 to the reversing valve IE, but' through the conduit I6, 40 I8 comprising a, throttle valve II which may be adjusted by hand as desired. The liquid under pressure is therefore regulated by the throttle valve and by means of the device described the table speed otherwise provided during the work- 45 ing operation is replaced by another speed,

namely the lower speed necessary for truing the grinding wheeL The link 14 is furthermore connected to a three-armed lever I9 adapted to rock about the 50 point 80. During the upward movement of the link I4, the said lever makes a rotation in the clockwise direction, carrying with it the link 3|, which is pivoted by its second end to a double lever 82 and this double lever in its turn lifts 55 the link 83 which is connected to its second arm and which is also conn'ected'to the rod- 34 running in fixed guides and also raising the said rod. The said rod 84 forms an abutment for an arm 05 whichis mounted on the same shaft 60 as a toothed sector 86. The toothed sector meshes with a further toothed sector on a second shaft carrying the truing device 8]. When the rod 84 is raised and the abutment arm 85 comes into engagement with it, the arm with the 65 truing device is thereby erected and brought into different positions. In the one position, shown Fuller explanation is v by spindles are common knowledge. Mounted on the spindle 90, which in the drawings is shown rotated through 90 from its actual position, is a ratchet wheel 09. Loose on the same shaft is also a pawl lever 89a which is connected by a link 33 to the third arm of the lever I9. Thus, the rocking of the three-armed lever 19 effects, in addition to the adjustment of the abutment 34, also the necessary feed of the grinding wheel for truing. After truing, the truing apparatus 31 is turned over again by a cam 93 fixed to the frame acting upon the surface 81a of the truing apparatus.

During the time in which the shaft 30 is rotated by the table through the medium of the ratchet wheel 33, the hydraulic gear must be stopped. This purpose is served by the cam 34 which engages a lever 94. The lever 94 is connected by the link 95 to the stop valve 24 for the gear, and when a suitable recess in the cam 34 arrives opposite the cam follower of the lever 34, the, spring 96 reverses the valve 24 and the oil under pressure is shut off from the gear 23- and flows through the conduit 25a into the oiltank. The cam 34 is so adapted that it always stops the gear in the manner described at the times at which the shaft 30 is to be moved by the table, while at other times it reverses the valve 24 again so that the shaft 30 can then be rotated by the gear 23 in the manner described hereinbefore. The times during which the shaft is driven in one way or the other follow one upon the other.

The cams 35 and 35 serve for regulating the table speed by adjusting the throttle valve I4. The latter is connected by a link to a lever 91. This lever may be rocked either about its end point 38 or about the pin I00 situated substantially in its centre. The said pin is eccentrically mounted. The eccentric is provided with a hand lever 39. By rocking the hand lever 99, the lever 31 is consequently swung about the end point 33. The valve I4 is thereby adjusted and therefore throttles more or less the liquid flowing to the cylinder 3.

In addition to this possibility of manual adjustment a further adjustment by the cams is also provided, and for this purpose, pivoted to the point 33 of the lever 91 is a link I01, attached to which is one arm I09 of a three-armed lever adapted to rock about the point I I0. The other two arms I03 and I00a of the said lever engage the cam 35, by which the lever is rocked at the suitable time. In doing so it carries with it'the lever 31 and adjusts the throttle valve. Pivoted to the end point I06 of the link I01 is a rod I03, the free end point of which is adjustable relatively to two stops IN and I02. By the movement of the link I01 and hence also of the rod I03 to the right in the drawings, the rate of flow of liquid to-the cylinder 3 is increased, i. e. the throttle valve I4 isopened wider. The cam 35 is adapted ,to rock the lever until the rod I03 abuts against one of the stops IM and I02. The stops are adjustable by hand.

The adjustment of the rod I03 relatively to one or other of the stops is effected by the cam 35 which cooperates with a lever I04. The latter is connected by a link I05 with the rod I03. The cam 33 acts so that on changing over from one method of machining to the othenthat is to say for example, on changing over from roughing to finishing and conversely, the rod I03 is ad justed relatively to the one or the other of the stops. The three-armed lever I08, l08a, I00 is -made in two parts, i. e. the arm I09 is connected 2 workin to the arms I08 and I 08a by a friction coupling, so that independently of the stroke made by the cam 35, the rod can be arrested by the stop IOI or I02. In its left hand end position, the lever I09 5 bears against a stop-pin III.

The machine may also be operated by hand by rotating the hand-wheel I20. For this purpose, mounted parallel to the shaft 30 is a further shaft II2 adapted to be rotated by a handle H3. This v 10 shaft carries a number of eccentrics II4 and a '0 ment surface III fixed on said sector I" and remains inoperative.

In this way, by rotation of the shaft II2, the cams (with the exception of cams 32, 36, Ma which are necessary even for the nonautomatic g of the machine) are renderedinoperative and the machine can now be controlled by hand, i. e., worked non-automatically if desired, e. g., when carrying out an operation which will not be repeated. 30 The cam 34 may likewise be rendered inoperative, although this is not necessary nor are any means indicated in the drawings for this purpose. If the cam 34 is in the operative position during manual operation and the workman for- 35 gets to allow the table to travel to the end position, the cam acts upon the cock 24 by rotation of the shaft 30, and at the end of each machining operation, 1. e., rough grinding or finishing, the gear is automatically stopped.

40 The operation of the machine is consequently as follows:

At the commencement of the working operation, when a fresh work piece is to be mounted, the table is at rest' in the left-hand position.

45, The cam 44 hasdepressed the roller 45 and the valve has been opened by the parts 55, 59, 62 in the manner described hereinbefore, so that the pump runs idle, since the reversing valve I6 is in the position in which the pressure fluid is fed 50 to the conduit I'I.

, After clamping the work in the work holder situated on the table -I but not shown in the drawings, the machine is started by a pressure on the knob 64. The rod 55 releases the lever 59 so 55 that the'valve 63 can close again under the: action of the spring 66 and the table now starts to run to the right, the cam 42 coming into contact with the roller 43 and pressing the latter downwardly. At this time the pawl 54 is within range of the 00 notch I of the locking cam 33. By the depression of the when, the pawl lever 54 is rotated and thereby the shaft 30 is rotated by a certain amount. I

control movements are carried out on the cams .05 mounted on the shaft 30.

The cam 3| does not make any control movement, but on the contrary the cam lever 56 remains in the previously existing position. The cam 32,.shortly before the completion of the 0 travel of the .table for clamping the work, had a position in which the cam lever. was engaged. Consequently, the rods '50-, 52 had rendered the stop 6 inoperative and the continued movement of the table I 'tothe left had become possible.

Immediately thereupon, however, namely after During this roughing, the grinding wheel must By this short rotation, the followingthe stop 5 had passed the stop 6, the shaft 30 had rotated the cam lever 48 in the anticlockwise direction, thereby lowering the rod 52 and bringing the stop 6 into the operative position again. Now, during the movement of the table to the 5 right, the said stop 6 lifts as it passes over the inclined surface of the stop 5 so that the lever is not displaced.

The cam.34, whichlpreviously was in a positlon m which the lever 94 was eng ged and the m valve 24 shut, is brought by the aforesaid short rotation of the shaft 30 into the position shown in the drawings, and thereby the flow of oil to the gear 23 is started. Therefore, directly after the rotation of the shaft 30 by theratchet wheel 33, the hydraulic drive of the shaft commences. rThe cam moves the lever I09 and the rods I01, I03 connected therewith to the right towards the stop I02 situated at this time in the operative position. Consequently, the working 20 speed necessary for roughing is adjusted at the throttle valve I4. The adjustment of the rod I03 in front of the stop I02 has been effected by the cam 36 on the previous outward movement of the table with the finished work. The cam 31 during this said time has no control to carry out. In the further movement of the table to theright which is now effected by the pressure oil delivered by the pump 9, machining of the work is effected, the stop 6 effecting the reversal of the table in co-operation with the two stops 4 and 5," adjusted according to the length of the work to be machined. The first working operation is the roughing or preliminary grinding of the work.

be fed in to the work. This is eflected by the? hydraulic gear 23 acting through the parts 26, v: 21, 28, 29, 30, 38, 39, 40, 4|, 4Ia. As soon as the roughing operation is completed, the cam 32 becomes operative, the lever' 48 again swings out in the clockwise direction and acting through the rods 50 and 52 moves the stop out of the path of the stops. Consequently, the table now travels to the left beyond its working position.

During this time, the lever I04 is lifted out of the recess of the cam 36, thereby rotating the rod I03 about its pivot I06 and rocking it into the position'shown in the drawings in which it is opposite the finishing stop IN. The cam 35 and lever I09, which previously'had moved the rod I03 so far to the left that it is freefrom the stops IOI, I02 now brings the rod I03 into contact with the stop IOI, thereby adjusting the throttle valve I4 to the speed necessary for finishing. Simultaneously, the cam 31 also has rotated until the farthat the cam 46 comes into engagement with the roller 4I,'the rods 68, 69 will bring into operation the abutment surface I0 and the reversing valve I2 will be moved by the push rod I2 and the lever I5 so that the passage I3 is closed and .65 the liquid from the pump 9 now proceeds through the passage I6 in accordance with the adjustment of the throttle screw II. A tablespeed is now adjusted which is necessary for truing the wheel. 70

Simultaneously, the rods I3, I4 will have rotated the three-armed lever I9 and the latter through the medium of the rods BI, 82, 83 will have lifted the rod 84 so that on the continued movement of the table to the left, the stop 05 .75

abuts against the stop 84 and the truing apparatus is erected. Simultaneously, the threearmed lever 19 by means of the ratchet wheel 89a will have rotated the cross-feed screw 90 for the grinding wheel, so that the latter is fed the necessary amount towards the truing diamond and now as the truing diamond passes the grinding wheel, the latter willbe trued. On the abutment of the cam 42 against the roller 43, the pawl lever 54 has again been rocked. The pawl of this lever has thereby come into engagement with the tooth II of the ratchet wheel 33 and by the movement of the pawl lever a further rotation of the shaft 30 has been effected by the arm 54. By this brief rotation of the shaft, the cam 32 is brought into the position in which the bell-crank lever 48 can again .drop in, so that through the medium of the rods 50, 52, the stop 5 can again return to its initial I m position.

When after roughing the table moves to the left, the cam 3| rotates the lever 56 in the clockwise direction, so that the nose 50 is released from the lever 59- and the hydraulic table drive 25 remains in gear during truing and finishing.

When the table moves further to the left, the truing device passes the grinding disc and trues it, and the movement to the left is continued until the stop l2! on cam 44 mounted on the 30 table comes into engagement with the stop 6 and thereby effects a reversal of the direction of travel of the table. As soon as the movement to theright has advanced so far that the diamond has released the grinding wheel again, the cam 35 46 also releases the roller 41 and the spring 9| pulls the lever 69 back and the springl l9 again throws over the valve I2, so that the table again travels at the normal speed. The cam'93 turns the truing device back into its inoperative position.

On the further movement, the cam 44 also releases the roller 45, while the cam 42 comes into engagement with the roller 43 and presses the latter downwardly. There thus takes place another further movement of the shaft 30 by the pawl lever 54 which at this time is just within range of the notch III. The cam 34 is adapted so that whenever the shaft 30 is advanced by the ratchet wheel 33, the valve 24 is closed.

5 Upon the last-mentioned rotation of the shaft 30 by the ratchet tooth III, the lever 56 again runs on to the elevated part of the cam 3|, so

that the stop 59 is again moved in front of the nose 50. The cam 34 again throws over the valve 55 24, so that the drive is again effected by the gear 23. i

The further cross-feed of the grinding spindle in the finishing operation which now commences is effected by the crom-feed gear 23. When the g extreme cross-feed position is attained, that is to say, when finishing is completed, the cam 32 again renders the stop 6 inoperative and in the meantime the notch IV has come within range of the pawl lever 54. The cam- 34 now shuts ofl.

5 the gear 23 again, the table runs to the left again,

' since the stop 6 is disengaged, and due to the cam 42 running on the roller 43, the shaft is rotated further through a certain amount by the pawl 54. The stop 6 is thereby released again and re- 70 turns into the operative position. The cam 35 draws the lever I09 back again so that it bears against the stop Ill and the cam 36 moves the rod I03 downwardly opposite the roughing stop I52. Upon the further movement of the table 'to the left, first the stop H8 engages the stop 5 and shifts the reversing valve It to allow a movement of the table to the right and immediately thereupon the cam 44 comes into engagement with the roller, thereby disengaging the valve 63 through the medium of the rods 55, 59, 52 so that the machine stops. The completely machined work can now be removed and replaced by a fresh piece of work, whereupon machining of this fresh piece of work can be set in operation by pressure upon the knob 64.

The constructional execution of the machine is of course optional. Instead of the cam mechanism described it is also possible to employ link mechanism. and likewise electrical or mechanical devices may be employed instead of the hydraulic motors.

I claim:-- 4

1. An automatic internal grinding machine comprising, in combination with mechanisms for carrying out the actual feed movements of the tool, the machirie table carrying the work and the truing tool, cams adapted to. carry out all thecontrol movements for the said feed movements, a shaft driving the said cams, said cams being so devised that the position of all parts controlled by them at the end of each working operation is exactly the same as at the commencement thereof, and two means adapted to turn said shaft for one complete revolution during one working operation, each means driving said shaft during a part of each revolution.

2. An automatic internal grinding machine according to claim 1, and in which of'the two means one is independent of the feeding movement of the machine table and serves for drivin the shaft during the machining operations (roughing, finishing) and the other is derived i 4. An automatic internal grinding machinev according to claim 1, and in which of the two means one is a hydraulic gear and serves for driving the shaft during the machining operations and also for cross-feeding the tool during machining and the other is derived from the drive of the machine table, the hydraulic driving means of the cam shaft being rendered inoperative during the rotation of the latter by the means derived from the machine table.

5. An automatic internal grinding machine comprising, in combination with mechanisms for carrying out the actual feed movements of the tool, the machine table carrying the work, and the truing tool, six cams adapted to carry out all the control movements for the said feed movements, a starting and stopping device for the table movement controlled by one of the cams,

. a stop for controlling the reciprocatory movement of the grinding wheel for the purposes of truiiig controlled by a sixth of said cams, a shaft driving the said cams and means adapted to turn said shaft for one complete revolution during one working operation, said cams being so devised that the portion of all parts controlled by them at the end of each working operation is exactly the same as at the commencement thereof.

6. An automatic internal grinding machine comprising, in combination with mechanisms for carrying out the actual feed movements of the tool, the machine table carrying the work, and the truing tooL'c'ams adapted'to carry out all the control movements for the said feed movements, a shaft driving the said cams and means adapted to turn said last mentioned means comprising a ratchet wheel mechanism, and means for'operating same, a cam connected with the table and setting said ratchet wheel mechanism in operation, and a driving means, said mechanism cooperating with the cam controlling the stopping of the driving means so that the pawl engages a ratchet tooth as soon as the latter driving means is stopped.

'7. An vautomatic internal grinding machine according to'claim 1, in which table 'stops'are provided on the machine table and a butt strap engaged by said stops at the ends of each working movement thereby efiecting the reversal of the table and on which a lever mechanism is arranged controlled by said shaft and adapted to bring said butt strap out of the path of the said stops.

8. An automatic internal grinding machine according to claim 1, in which a hydraulic drive is provided for the feed movement of the machine table, a liquid tank and aliquid supply for said drive, the said liquid supply comprising a reversing valve for adjusting the various speeds for the working operation and truing operation, a throttle valve for regulating the speeds for the various working operations, a reversing valve for the table movement and a cut-off valve by which the supply of oil is brought into communication with the liquid tank.

9. An automatic internal grinding machine according to claim 1, in which the control movement of the cams is effected by means of cam levers and means are provided adapted to lift said cam levers commonly off their cams thereby making them inoperative.

10. An automatic internal grinding machine accordingto claim 1, in which the control movement of the cams is effected 'by means of cam levers and means are provided adapted tov lift said ca m levers commonly oif their cams thereby making them inoperative and further hand-operated means adapted to efiect then the control of the machine by hand.

KARL JUNG. 

